Cement/Admixture Incompatibility: Fact or Fallacy?

True cement/admixture incompatibility is very rare. Unfortunately, common performance problems are often misdiagnosed as cement/admixture incompatibility, and the price of this misdiagnosis is paid later.
Many variables influence the performance of a combination of cement and admixtures. Being aware of some of the variables of admixture performance may help you determine if there is a compatibility problem. Some problems are caused by inconsistencies in they type of cement used. Water content, age of concrete, mixing, dosage rate, aggregate moisture, and temperature can all cause low slump, which is one of the symptoms commonly misdiagnosed as cement/admixture incompatibility. Slow-setting concrete is almost never a result of incompatibility. Instead, it usually indicates a healthy relationship between cement and admixtures. Low compressive strength is more likely to be caused by other factors than incompatibility.
When incompatibility is suspected, always make sure to rule out all other possibilities before acting.